Acorn Flour & Oil

Oak is an oft-overlooked native food source with significant potential as a tree crop. Oak, hickory, and chestnut were keystone species in the woodland ecologies of precolonial North America, and it is no coincidence they were also keystone foods for many native peoples. There is an abundance of evidence that native peoples of this continent pruned and tended their woodland landscape to select for these species, both as versatile, storage-friendly staple calories and as fodder for game animals. Oak remains a keystone species of critical ecological importance. Of all plant genera in the Eastern Woodlands, oak is the single most “generous” — offering food and habitat to more birds, bugs, and other wildlife than any other member of our living community. Thus, incorporating oaks into agricultural landscapes offers big opportunities to enhance wildlife habitat.

As a food, acorn falls on a spectrum between chestnuts (mostly carbs, some fat and protein) and walnuts (mostly fat, some carbs and protein). Acorns generally offer a balanced profile of carbs and fat, with some protein. Many acorns are well suited to be dried and ground into flour, and some (more fatty) acorns are well suited to be pressed into oil. Sam Thayer’s “Nature’s Garden” documents the author’s deep experience and experimentation with harvesting and processing acorns into both flour and oil.

Oak trees live for hundreds of years, and the top 10% of the population appears capable of producing enormous yields that should be more than commercially viable on a per acre basis. Oaks have often been thought of as not a promising tree crop due to the perception of slow growth rates, and the fact that acorns contain tannins that need to be leached to make them edible. But hybrid oaks mature much more quickly than most people realize — often bearing within 4-7 years. And removing tannins at an industrial post-harvest scale is much less laborious than doing so at a home scale. Active acorn food industries already exist in Spain, Portugal, and South Korea, offering templates for agronomics, harvest, and post-harvest processing.

Chestnuts have only become commercially viable and scalable due to the germplasm and agronomic R&D done in the 20th century by generations of citizen scientists and breeders. If someone did the same R&D for oak (and hickory), these species could form the foundation of new perennial staple food agricultures and industries, with substantial positive impact on regional food security and ecological health. Like hickory, oak has potential both as an orchard crop and as a forest product. Our friend and colleague Eric Toensmeier’s "The status of oak breeding and domestication as food for people and livestock" is a good primer on the topic of the development of acorn as a food in the U.S.

This work has the potential for transformative impact, but is receiving virtually zero attention from existing research institutions in the U.S. In 2025-2028, with a consortium of partners, Breadtree Farms is conducting germplasm R&D and establishing ~15 acres of breeding orchards for native and hybrid oaks in both white and red groups, aimed at both flour and oil production. If this project is successful, it will yield a marketable crop of flour (and maybe oil), and a pool of excellent genetics from which many farmers could establish the next generation of acorn orchards.

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